Deng Tongchu, Chen Xingjuan, Zhang Qin, Zhong Yuming, Guo Jun, Sun Guoping, Xu Meiying
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China.
State Key Laboratory of Applied Microbiology Southern China, Guangzhou 510070, PR China.
Int J Syst Evol Microbiol. 2017 Nov;67(11):4710-4715. doi: 10.1099/ijsem.0.002367. Epub 2017 Oct 6.
Two facultative chemolithotrophic, nitrate-reducing thiosulfate-oxidizing strains, F43b and F21, were isolated from the sulfide-rich anoxic sediment of an urban creek in Pearl River Delta, China. Both strains were Gram-negative, facultatively anaerobic, non-spore-forming and rod-shaped with a flagellum. Phylogenetic analyses of 16S rRNA genes and the thrC, recA, glnII and atpD housekeeping genes revealed that the type strain shared high sequence similarities to Ciceribacter lividus MSSRFBL1, with 98.8, 90.9, 94.8, 95.4 and 96.1 % identity, respectively. In addition, the major isoprenoid quinone (ubiquinone Q-10) and the DNA G+C content (66.0 mol%) of the type strain were similar to those of Ciceribacter lividus MSSRFBL1. These results strongly support the classification of strains F43b and F21 into the genus Ciceribacter. However, these strains diverged markedly from strain MSSRFBL1 with respect to several physiological and biochemical properties such as their semi-translucent colonies and nitrate-reducing and simultaneous thiosulfate-oxidizing respiration. Furthermore, the predominant fatty acids of strain F43b were summed feature 2 (C18 : 1ω9t and/or C18 : 1ω9c and/or C18 : 1ω11t), C14 : 0 3-OH, C18 : 0 and C16 : 0, and its polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidymonomethylethanolamine and an unidentified glycolipid, which represented another two significant differences from strain MSSRFBL1. Importantly, the DNA-DNA relatedness between strain F43b and MSSRFBL1 was only 47.7 %. Based on the aforementioned polyphasic taxonomic results, the two isolates are suggested to represent a novel species of the genus Ciceribacter, for which the name Ciceribacterthiooxidans sp. nov. is proposed; the type strain is F43b (=CCTCC AB 2016062=KCTC 52231).
从中国珠江三角洲一条城市小溪富含硫化物的缺氧沉积物中分离出两株兼性化能无机营养型、硝酸盐还原型硫代硫酸盐氧化菌株F43b和F21。两株菌株均为革兰氏阴性、兼性厌氧、无芽孢形成且具鞭毛的杆状菌。对16S rRNA基因以及看家基因thrC、recA、glnII和atpD进行系统发育分析，结果表明模式菌株与淡紫西塞罗杆菌MSSRFBL1具有较高的序列相似性，同一性分别为98.8%、90.9%、94.8%、95.4%和96.1%。此外，模式菌株的主要类异戊二烯醌（泛醌Q-10）和DNA G+C含量（66.0 mol%）与淡紫西塞罗杆菌MSSRFBL1相似。这些结果有力地支持了将菌株F43b和F21归为西塞罗杆菌属。然而，这些菌株在一些生理生化特性方面与菌株MSSRFBL1明显不同，如它们的半透明菌落、硝酸盐还原和同时进行硫代硫酸盐氧化呼吸。此外，菌株F43b的主要脂肪酸为特征性总和2（C18:1ω9t和/或C18:1ω9c和/或C18:1ω11t）、C14:0 3-OH、C18:0和C16:0，其极性脂为双磷脂酰甘油、磷脂酰乙醇胺、磷脂酰单甲基乙醇胺和一种未鉴定的糖脂，这是与菌株MSSRFBL1的另外两个显著差异。重要的是，菌株F43b与MSSRFBL1之间的DNA-DNA相关性仅为47.7%。基于上述多相分类学结果，建议这两个分离株代表西塞罗杆菌属的一个新物种，为此提出新名称硫氧化西塞罗杆菌（Ciceribacterthiooxidans sp. nov.）；模式菌株为F43b（=CCTCC AB 2016062=KCTC 52231）。
